Plant-Microbe Symbiosis
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2013 Fungal Genetics Conference (Asilomar, USA, March 12-17, 2013)

2013 Fungal Genetics Conference (Asilomar, USA, March 12-17, 2013) | Plant-Microbe Symbiosis | Scoop.it

The Fungal Genetics Policy Committee invites you to attend the 27th Fungal Genetics Conference, sponsored by the Genetics Society of America. The meeting is held every two years at the Asilomar Conference Grounds, Pacific Grove, California (near Monterey, California). The conference will open on Tuesday evening, March 12 with an Opening Mixer from 7:30 pm – 10:30 pm and end on Sunday, March 17. Regine Kahmann will present the Perkins/Metzenberg Lecture on Saturday, March 16 at 6:30 pm, followed by the banquet and closing party.

 

Chairs of the Scientific Program:
Katherine Borkovich, University of California, Riverside
Francis Martin, INRA, Nancy, France


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Plant-Microbe Symbiosis
Beneficial associations between plants and microbes
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The physiology and habitat of the last universal common
ancestor

The physiology and habitat of the last universal common<br/>                    ancestor | Plant-Microbe Symbiosis | Scoop.it
A phylogenetic approach was used to illuminate the physiology of the last universal common ancestor, supporting the theory that LUCA was an H2-dependent autotroph in a hydrothermal setting rich in hydrogen, carbon dioxide and iron.

Via Loïc Lepiniec
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LUCA was fixing nitrogen... I am excited to see that our ancestor was fixing nitrogen.

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Intraradical colonization by arbuscular mycorrhizal fungi triggers induction of a lipochitooligosaccharide receptor

Intraradical colonization by arbuscular mycorrhizal fungi triggers induction of a lipochitooligosaccharide receptor | Plant-Microbe Symbiosis | Scoop.it
Functional divergence of paralogs following gene duplication is one of the mechanisms leading to evolution of novel pathways and traits. Here we show that divergence of Lys11 and Nfr5 LysM receptor kinase paralogs of Lotus japonicus has affected their specificity for lipochitooligosaccharides (LCOs) decorations, while the innate capacity to recognize and induce a downstream signalling after perception of rhizobial LCOs (Nod factors) was maintained. Regardless of this conserved ability, Lys11 was found neither expressed, nor essential during nitrogen-fixing symbiosis, providing an explanation for the determinant role of Nfr5 gene during Lotus-rhizobia interaction. Lys11 was expressed in root cortex cells associated with intraradical colonizing arbuscular mycorrhizal fungi. Detailed analyses of lys11 single and nfr1nfr5lys11 triple mutants revealed a functional arbuscular mycorrhizal symbiosis, indicating that Lys11 alone, or its possible shared function with the Nod factor receptors is not essential for the presymbiotic phases of AM symbiosis. Hence, both subfunctionalization and specialization appear to have shaped the function of these paralogs where Lys11 acts as an AM-inducible gene, possibly to fine-tune later stages of this interaction.

Via Ryohei Thomas Nakano
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Grasses suppress shoot-borne roots to conserve water during drought

Many important crops are members of the Poaceae family, which develop root systems characterized by a high degree of root initiation from the belowground basal nodes of the shoot, termed the crown. Although this postembryonic shoot-borne root system represents the major conduit for water uptake, little is known about the effect of water availability on its development. Here we demonstrate that in the model C4 grass Setaria viridis, the crown locally senses water availability and suppresses postemergence crown root growth under a water deficit. This response was observed in field and growth room environments and in all grass species tested. Luminescence-based imaging of root systems grown in soil-like media revealed a shift in root growth from crown-derived to primary root-derived branches, suggesting that primary root-dominated architecture can be induced in S. viridis under certain stress conditions. Crown roots of Zea mays and Setaria italica, domesticated relatives of teosinte and S. viridis, respectively, show reduced sensitivity to water deficit, suggesting that this response might have been influenced by human selection. Enhanced water status of maize mutants lacking crown roots suggests that under a water deficit, stronger suppression of crown roots actually may benefit crop productivity.

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Phytochemicals induced in chickpea roots selectively and non-selectively stimulate and suppress fungal endophytes and pathogens

Phytochemicals induced in chickpea roots selectively and non-selectively stimulate and suppress fungal endophytes and pathogens | Plant-Microbe Symbiosis | Scoop.it
Aims

Plant roots shape the structure of the soil microbiome by producing a wide array of phytochemicals, which in turn impact plant growth and health. The synthesis of root metabolites is a dynamic process that is modulated by interactions with soil microorganisms. This study explored the regulation of soil-borne fungal endophytes and pathogens by the production of phytochemicals in chickpea (Cicer arietinum L.) roots colonized or not colonized by the arbuscular mycorrhizal (AM) fungus Rhizophagus irregularis.

Methods

Proteins and low-molecular-mass phytochemicals were extracted from chickpea roots and fractionated by flash chromatography and high pressure liquid chromatography (HPLC). The effects of these metabolites on the soil-borne fungal endophytes Trichoderma harzianum and Geomyces vinaceus and on the pathogens Fusarium oxysporum and Rhizoctonia solani were tested in 96-well plate assays.

Results

One protein fraction from the AM roots, which contained an apparent 34 KDa chitinase/chitin-binding domain and 24 KDa non-specific lipid transfer protein, non-selectively repressed the fungal endophytes and pathogens. By contrast to the protein fraction, the low-molecular-mass fractions were often selective. Eighteen fractions stimulated specific fungal species and seven fractions inhibited others.

Conclusions

Several protein and low-molecular-mass phytochemicals in chickpea roots influence fungal endophytes. The difference in the response of fungal species to the phytochemicals suggests that these metabolites could be involved in the so called host ‘preference’ of fungal endophytes or ‘resistance’ to pathogens. This research reveals that the majority of the bioactive root metabolites could be involved in the selective association of chickpea and fungal endophytes while a few compounds provided resistance by suppressing the pathogenic species.
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The elusive predisposition to mycoheterotrophy in Ericaceae

The elusive predisposition to mycoheterotrophy in Ericaceae | Plant-Microbe Symbiosis | Scoop.it
The rise and diversification of land plants was accompanied by mycorrhizal symbiosis, from their emergence to their adaptation to various biomes and ecological situations (Selosse et al., 2015). In most mycorrhizal associations, fungi provide soil minerals to the plant, in exchange for sugars derived from photosynthesis (Smith & Read, 2008; van der Heijden et al., 2015). However, several plant species adapted to shaded forest conditions by secondarily reversing this exchange of carbohydrates: they became achlorophyllous thanks to carbon provided by the fungus. This so-called mycoheterotrophic nutrition is described in over 400 species and evolved at least 40 times independently (Merckx, 2013), raising the question of what predispositions underlie these convergences.
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Frontiers | “Omics” Tools for Better Understanding the Plant–Endophyte Interactions | Plant Biotic Interactions

Frontiers | “Omics” Tools for Better Understanding the Plant–Endophyte Interactions | Plant Biotic Interactions | Plant-Microbe Symbiosis | Scoop.it
Endophytes, which mostly include bacteria, fungi and actinomycetes, are the endosymbionts that reside asymptomatically in plants for at least a part of their life cycle. They have emerged as a valuable source of novel metabolites, industrially important enzymes and as stress relievers of host plant, but still many aspects of endophytic biology are unknown. Functions of individual endophytes are the result of their continuous and complex interactions with the host plant as well as other members of the host microbiome. Understanding plant microbiomes as a system allows analysis and integration of these complex interactions. Modern genomic studies involving metaomics and comparative studies can prove to be helpful in unraveling the gray areas of endophytism. A deeper knowledge of the mechanism of host infestation and role of endophytes could be exploited to improve the agricultural management in terms of plant growth promotion, biocontrol and bioremediation. Genome sequencing, comparative genomics, microarray, next gen sequencing, metagenomics, metatranscriptomics are some of the techniques that are being used or can be used to unravel plant–endophyte relationship. The modern techniques and approaches need to be explored to study endophytes and their putative role in host plant ecology. This review highlights “omics” tools that can be explored for understanding the role of endophytes in the plant microbiome.

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Piriformospora indica Stimulates Root Metabolism of Arabidopsis thaliana

Piriformospora indica Stimulates Root Metabolism of Arabidopsis thaliana | Plant-Microbe Symbiosis | Scoop.it
Piriformospora indica is a root-colonizing fungus, which interacts with a variety of plants including Arabidopsis thaliana. This interaction has been considered as mutualistic leading to growth promotion of the host. So far, only indolic glucosinolates and phytohormones have been identified as key players. In a comprehensive non-targeted metabolite profiling study, we analyzed Arabidopsis thaliana’s roots, root exudates, and leaves of inoculated and non-inoculated plants by ultra performance liquid chromatography/electrospray ionization quadrupole-time-of-flight mass spectrometry (UPLC/(ESI)-QTOFMS) and gas chromatography/electron ionization quadrupole mass spectrometry (GC/EI-QMS), and identified further biomarkers. Among them, the concentration of nucleosides, dipeptides, oligolignols, and glucosinolate degradation products was affected in the exudates. In the root profiles, nearly all metabolite levels increased upon co-cultivation, like carbohydrates, organic acids, amino acids, glucosinolates, oligolignols, and flavonoids. In the leaf profiles, we detected by far less significant changes. We only observed an increased concentration of organic acids, carbohydrates, ascorbate, glucosinolates and hydroxycinnamic acids, and a decreased concentration of nitrogen-rich amino acids in inoculated plants. These findings contribute to the understanding of symbiotic interactions between plant roots and fungi of the order of Sebacinales and are a valid source for follow-up mechanistic studies, because these symbioses are particular and clearly different from interactions of roots with mycorrhizal fungi or dark septate endophytes
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A consolidated analysis of the physiologic and molecular responses induced under acid stress in the legume-symbiont model-soil bacterium Sinorhizobium meliloti

A consolidated analysis of the physiologic and molecular responses induced under acid stress in the legume-symbiont model-soil bacterium Sinorhizobium meliloti | Plant-Microbe Symbiosis | Scoop.it
Abiotic stresses in general and extracellular acidity in particular disturb and limit nitrogen-fixing symbioses between rhizobia and their host legumes. Except for valuable molecular-biological studies on different rhizobia, no consolidated models have been formulated to describe the central physiologic changes that occur in acid-stressed bacteria. We present here an integrated analysis entailing the main cultural, metabolic, and molecular responses of the model bacterium Sinorhizobium meliloti growing under controlled acid stress in a chemostat. A stepwise extracellular acidification of the culture medium had indicated that S. meliloti stopped growing at ca. pH 6.0–6.1. Under such stress the rhizobia increased the O2 consumption per cell by more than 5-fold. This phenotype, together with an increase in the transcripts for several membrane cytochromes, entails a higher aerobic-respiration rate in the acid-stressed rhizobia. Multivariate analysis of global metabolome data served to unequivocally correlate specific-metabolite profiles with the extracellular pH, showing that at low pH the pentose-phosphate pathway exhibited increases in several transcripts, enzymes, and metabolites. Further analyses should be focused on the time course of the observed changes, its associated intracellular signaling, and on the comparison with the changes that operate during the sub lethal acid-adaptive response (ATR) in rhizobia.

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Mixed Nodule Infection in Sinorhizobium meliloti–Medicago sativa Symbiosis Suggest the Presence of Cheating Behavior

Mixed Nodule Infection in Sinorhizobium meliloti–Medicago sativa Symbiosis Suggest the Presence of Cheating Behavior | Plant-Microbe Symbiosis | Scoop.it
In the symbiosis between rhizobia and legumes, host plants can form symbiotic root nodules with multiple rhizobial strains, potentially showing different symbiotic performances in nitrogen fixation. Here, we investigated the presence of mixed nodules, containing rhizobia with different degrees of mutualisms, and evaluate their relative fitness in the Sinorhizobium meliloti–Medicago sativa model symbiosis. We used three S. meliloti strains, the mutualist strains Rm1021 and BL225C and the non-mutualist AK83. We performed competition experiments involving both in vitro and in vivo symbiotic assays with M. sativa host plants. We show the occurrence of a high number (from 27 to 100%) of mixed nodules with no negative effect on both nitrogen fixation and plant growth. The estimation of the relative fitness as non-mutualist/mutualist ratios in single nodules shows that in some nodules the non-mutualist strain efficiently colonized root nodules along with the mutualist ones. In conclusion, we can support the hypothesis that in S. meliloti–M. sativa symbiosis mixed nodules are formed and allow non-mutualist or less-mutualist bacterial partners to be less or not sanctioned by the host plant, hence allowing a potential form of cheating behavior to be present in the nitrogen fixing symbiosis.

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UW-Madison scores high in world university rankings

UW-Madison scores high in world university rankings | Plant-Microbe Symbiosis | Scoop.it
For the third year in a row, the University of Wisconsin—Madison has been ranked 25th worldwide by the Center for World University Rankings.
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Yeah!!

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Sc2.0 | Synthetic Yeast 2.0

Welcome to Sc2.0, the synthetic yeast genome web site.

This is the site where you will learn about our ongoing project to synthesize the genome – from oligos to chromosomes, and the design features of the new version of Saccharomyces cerevisiae which we fondly refer to as Sc2.0.

Also, these pages describe the Build-A-Genome course, an innovative educational program to engage undergraduate students and others directly in the Sc2.0 project by producing Building Blocks that will be directly used in the project.

These pages also serve as a forum for engaging the yeast and synthetic biology communities in a new initiative to synthesize a modified version of the genome, chromosome by chromosome, from the “bottom up”. We welcome input on the best design features for yeast 2.0 – or future versions. An important aspect of this will be to leverage the formidable collective knowledgebase of the yeast and synthetic biology communities.
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High-resolution genetic maps of Lotus japonicus and L. burttii based on re-sequencing of recombinant inbred lines

High-resolution genetic maps of Lotus japonicus and L. burttii based on re-sequencing of recombinant inbred lines | Plant-Microbe Symbiosis | Scoop.it
Recombinant inbred lines (RILs) derived from bi-parental populations are stable genetic resources, which are widely used for constructing genetic linkage maps. These genetic maps are essential for QTL mapping and can aid contig and scaffold anchoring in the final stages of genome assembly. In this study, two Lotus sp. RIL populations, Lotus japonicus MG-20 × Gifu and Gifu × L. burttii, were characterized by Illumina re-sequencing. Genotyping of 187 MG-20 × Gifu RILs at 87,140 marker positions and 96 Gifu × L. burttii RILs at 357,973 marker positions allowed us to accurately identify 1,929 recombination breakpoints in the MG-20 × Gifu RILs and 1,044 breakpoints in the Gifu × L. burttii population. The resulting high-density genetic maps now facilitate high-accuracy QTL mapping, identification of reference genome mis-assemblies, and characterization of structural variants.

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Availability and function of arbuscular mycorrhizal and ectomycorrhizal fungi during revegetation of dewatered reservoirs left after dam removal

Availability and function of arbuscular mycorrhizal and ectomycorrhizal fungi during revegetation of dewatered reservoirs left after dam removal | Plant-Microbe Symbiosis | Scoop.it
Revegetation following dam removal projects may depend on recovery of arbuscular mycorrhizal (AM) and ectomycorrhizal (EM) fungal communities, which perform valuable ecosystem functions. This study assessed the availability and function of AM and EM fungi for plants colonizing dewatered reservoirs following a dam removal project on the Elwha River, Olympic Peninsula, Washington, United States. Availability was assessed via AM fungal spore density in soils and EM root tip colonization of Salix sitchensis (Sitka willow) in an observational field study. The effect of mycorrhizal fungi from 4 sources (reservoir soils, commercial inoculum, and 2 mature plant community soils) on growth and nutrient status of S. sitchensis was quantified in a greenhouse study. AM fungal spores and EM root tips were present in all field samples. In the greenhouse, plants receiving reservoir soil inoculum had only incipient mantle formation, while plants receiving inoculum from mature plant communities had fully formed EM root tips. EM formation corresponded with alleviation of phosphorus stress in plants (lower shoot nitrogen:phosphorus). Thus, revegetating plants have access to AM and EM fungi following dam removal, and EM formation may be especially important for plant P uptake in reservoir soils. However, availability of mycorrhizal fungi declines with distance from established plant communities. Furthermore, EM fungal communities in recently dewatered reservoirs may not be as effective at forming beneficial mycorrhizae as those from mature plant communities. Whole soil inoculum from mature plant communities may be important for the success of revegetating plants and recovery of mycorrhizal fungal communities.

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Decoding molecular interactions in microbial communities

Decoding molecular interactions in microbial communities | Plant-Microbe Symbiosis | Scoop.it
Microbial communities govern numerous fundamental processes on earth. Discovering and tracking molecular interactions among microbes is critical for understanding how single species and complex communities impact their associated host or natural environment. While recent technological developments in DNA sequencing and functional imaging have led to new and deeper levels of understanding, we are limited now by our inability to predict and interpret the intricate relationships and interspecies dependencies within these communities. In this review, we highlight the multifaceted approaches investigators have taken within their areas of research to decode interspecies molecular interactions that occur between microbes. Understanding these principles can give us greater insight into ecological interactions in natural environments and within synthetic consortia.

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We've Been Wrong About Lichen For 150 Years

We've Been Wrong About Lichen For 150 Years | Plant-Microbe Symbiosis | Scoop.it

Hundreds of millions of years ago, a tiny green microbe joined forces with a fungus, and together they conquered the world. It’s a tale of two cross-kingdom organisms, one providing food and the one other shelter, and it’s been our touchstone example of symbiosis for 150 years. Trouble is, that story is nowhere near complete.

 

A sweeping genetic analysis of lichen has revealed a third symbiotic organism, hiding in plain sight alongside the familiar two, that has eluded scientists for decades. The stowaway is another fungus, a basidiomycete yeast. It’s been found in 52 genera of lichen across six continents, indicating that it is an extremely widespread, if not ubiquitous, part of the symbiosis. And according to molecular dating, it’s probably been along for the ride since the beginning.

 

“I think this will require some rewriting of the textbooks,” said Catharine Aime, a mycologist at Purdue University and co-author on the study published today in Science.


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Peter Buckland's curator insight, July 23, 4:14 AM
A fascinating discovery
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Grasses suppress shoot-borne roots to conserve water during drought

Many important crops are members of the Poaceae family, which develop root systems characterized by a high degree of root initiation from the belowground basal nodes of the shoot, termed the crown. Although this postembryonic shoot-borne root system represents the major conduit for water uptake, little is known about the effect of water availability on its development. Here we demonstrate that in the model C4 grass Setaria viridis, the crown locally senses water availability and suppresses postemergence crown root growth under a water deficit. This response was observed in field and growth room environments and in all grass species tested. Luminescence-based imaging of root systems grown in soil-like media revealed a shift in root growth from crown-derived to primary root-derived branches, suggesting that primary root-dominated architecture can be induced in S. viridis under certain stress conditions. Crown roots of Zea mays and Setaria italica, domesticated relatives of teosinte and S. viridis, respectively, show reduced sensitivity to water deficit, suggesting that this response might have been influenced by human selection. Enhanced water status of maize mutants lacking crown roots suggests that under a water deficit, stronger suppression of crown roots actually may benefit crop productivity.

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Multiplex amplicon sequencing for microbe identification in community-based culture collections

Multiplex amplicon sequencing for microbe identification in community-based culture collections | Plant-Microbe Symbiosis | Scoop.it
Microbiome analysis using metagenomic sequencing has revealed a vast microbial diversity associated with plants. Identifying the molecular functions associated with microbiome-plant interaction is a significant challenge concerning the development of microbiome-derived technologies applied to agriculture. An alternative to accelerate the discovery of the microbiome benefits to plants is to construct microbial culture collections concomitant with accessing microbial community structure and abundance. However, traditional methods of isolation, cultivation, and identification of microbes are time-consuming and expensive. Here we describe a method for identification of microbes in culture collections constructed by picking colonies from primary platings that may contain single or multiple microorganisms, which we named community-based culture collections (CBC). A multiplexing 16S rRNA gene amplicon sequencing based on two-step PCR amplifications with tagged primers for plates, rows, and columns allowed the identification of the microbial composition regardless if the well contains single or multiple microorganisms. The multiplexing system enables pooling amplicons into a single tube. The sequencing performed on the PacBio platform led to recovery near-full-length 16S rRNA gene sequences allowing accurate identification of microorganism composition in each plate well. Cross-referencing with plant microbiome structure and abundance allowed the estimation of diversity and abundance representation of microorganism in the CBC.

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Root signals that mediate mutualistic interactions in the rhizosphere

Root signals that mediate mutualistic interactions in the rhizosphere | Plant-Microbe Symbiosis | Scoop.it
A recent boom in research on belowground ecology is rapidly revealing a multitude of fascinating interactions, in particular in the rhizosphere. Many of these interactions are mediated by photo-assimilates that are excreted by plant roots. Root exudates are not mere waste products, but serve numerous functions to control abiotic and biotic processes. These functions range from changing the chemical and physical properties of the soil, inhibiting the growth of competing plants, combatting herbivores, and regulating the microbial community. Particularly intriguing are root-released compounds that have evolved to serve mutualistic interactions with soil-dwelling organisms. These mutually beneficial plant-mediated signals are not only of fundamental ecological interest, but also exceedingly important from an agronomical perspective. Here, we attempt to provide an overview of the plant-produced compounds that have so far been implicated in mutualistic interactions. We propose that these mutualistic signals may have evolved from chemical defenses and we point out that they can be (mis)used by specialized pathogens and herbivores. We speculate that many more signals and interactions remain to be uncovered and that a good understanding of the mechanisms and ecological implications can be the basis for exploitation and manipulation of the signals for crop improvement and protection.

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Everything you own could one day be made from mushrooms

Everything you own could one day be made from mushrooms | Plant-Microbe Symbiosis | Scoop.it
Most people look at mushrooms as an ingredient in risotto or a one-way ticket to a psychedelic wonderland. Sophia Wang sees a different future for fungi.

Sitting on the back porch of a San Francisco coffee shop, she fans a piece of worn, indigo-colored leather made from fungi grown in her company's lab.

"It's a new thing in the world," Wang, CEO and cofounder of MycoWorks, says of the mushroom-like material.
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How do biological markets compare to the markets of economics?

After an introduction to biological markets written for non-biologists, I explore whether and to what extent natural markets, i.e. markets on which non-human traders exchange goods and services with members belonging to their own or to other species, can be compared to human ‘economic’ markets, i.e. the markets analysed by economists. Biological Market Theory (BMT) borrows jargon and ideas from economics, but was at least as much inspired by sexual selection theory, a collection of models of ‘mating markets’, including human mating markets. Here I ask two main questions: (1) Is there more than only a superficial resemblance between both types of markets? (2) Can the analysis of one yield insights about the other?
First, I consider the different forms of human trading and markets and propose some biological ones to which these can best be compared, e.g. companies trading goods in markets shaped by ‘comparative advantage’ to underground nutrient exchange markets between plants and rhizobial bacteria and mycorrhizal fungi; job and retail markets with pollination, seed dispersal and protection markets between plants and insects; ‘embedded markets’ with grooming markets in non-human primates and so forth. Then I look at some phenomena that are considered to be exclusive to human markets, such as common currencies and binding contracts, and ask whether these are indeed that exclusive. Finally I look at the common ground: negotiations that take place on several types of markets, natural or not; the honesty of advertisements, which is recognised as a major problem for both human and non-human clients; the biological equivalent of the market – firm dichotomy and the importance of the costs of partner choice, which are known to economists as ‘transaction costs’ and to sexual selection theoreticians as ‘search costs’. I conclude that there are several good reasons to have a closer look at those properties that set human and biological markets apart, but certainly also at those features that make them comparable to each other.

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Drought Stress Responses in Soybean Roots and Nodules

Drought Stress Responses in Soybean Roots and Nodules | Plant-Microbe Symbiosis | Scoop.it
Drought is considered to be a major threat to soybean production worldwide and yet our current understanding of the effects of drought on soybean productively is largely based on studies on above-ground traits. Although the roots and root nodules are important sensors of drought, the responses of these crucial organs and their drought tolerance features remain poorly characterized. The symbiotic interaction between soybean and rhizobia facilitates atmospheric nitrogen fixation, a process that provides essential nitrogen to support plant growth and development. Symbiotic nitrogen fixation is important for sustainable agriculture, as it sustains plant growth on nitrogen-poor soils and limits fertilizer use for crop nitrogen nutrition. Recent developments have been made in our understanding of the drought impact on soybean root architecture and nodule traits, as well as underpinning transcriptome, proteome and also emerging metabolome information, with a view to improve the selection of more drought-tolerant soybean cultivars and rhizobia in the future. We conclude that the direct screening of root and nodule traits in the field as well as identification of genes, proteins and also metabolites involved in such traits will be essential in order to gain a better understanding of the regulation of root architecture, bacteroid development and lifespan in relation to drought tolerance in soybean.
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Donor-Soil Microbes Drive Ecosystem Restoration | The Scientist Magazine®

Donor-Soil Microbes Drive Ecosystem Restoration | The Scientist Magazine® | Plant-Microbe Symbiosis | Scoop.it
Donor-soil microbes drive—and can speed up—the restoration of degraded farmland, scientists at the Netherlands Institute of Ecology in Wageningen have shown. The results of a six-year field test, published today (July 11) in Nature Plants, show the greatest ecosystem repair in formerly arable fields in which the team removed a thick layer of existing topsoil before applying a thin layer of microbe-rich donor soil.

“Of course, seeds of plants were also present in the donor soil,” study coauthor Jasper Wubs of the Netherlands Institute of Ecology told reporters during a press briefing. “But our study shows that it is in fact the soil organisms—such as the bacteria, fungi, and roundworms—which determine the direction of ecosystem restoration.”
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Second investigation report released regarding U Hawaii explosion

Second investigation report released regarding U Hawaii explosion | Plant-Microbe Symbiosis | Scoop.it
Earlier today, the University of Hawaii released a second investigation report into the lab explosion that caused a postdoctoral researcher to lose one of her arms. This report was by the University of California Center for Laboratory Safety; the first was by the Honolulu Fire Department. Still to come is the one by the Hawaii Occupational Safety & Health Division.
At the time of the explosion, postdoctoral researcher Thea Ekins-Coward had just finished combining hydrogen, carbon dioxide, and oxygen gases from high-pressure cylinders into a lower pressure container. The mixture was to be used as a feedstock to grow bacteria to produce bioplastics and biofuels.
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Stop and smell the fungi: Fungal volatile metabolites are overlooked signals involved in fungal interaction with plants

Stop and smell the fungi: Fungal volatile metabolites are overlooked signals involved in fungal interaction with plants | Plant-Microbe Symbiosis | Scoop.it
Diverse fungi are intimately associated with plants, and molecules secreted from both the plant and fungal sides play critical roles in the establishment of their associations and affect plant growth and health. Through evolutionary arms races or strategic alliances with plants, fungi and other microbes have invented a bewildering array of secreted molecules to parasitize or communicate with plants. Research empowered by omics data and tools has greatly advanced understanding of the nature, role and mechanism of action of many secreted fungal proteins that affect plants directly or indirectly. However, available information about fungal volatile metabolites with similar functions is quite limited. Through this review, we aim to stimulate expeditions to this vastly under-explored frontier of fungal chemical ecology.

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Hierarchical neighbor effects on mycorrhizal community structure and function

Hierarchical neighbor effects on mycorrhizal community structure and function | Plant-Microbe Symbiosis | Scoop.it
Theory predicts that neighboring communities can shape one another's composition and function, for example, through the exchange of member species. However, empirical tests of the directionality and strength of these effects are rare. We determined the effects of neighboring communities on one another through experimental manipulation of a plant-fungal model system. We first established distinct ectomycorrhizal fungal communities on Douglas-fir seedlings that were initially grown in three soil environments. We then transplanted seedlings and mycorrhizal communities in a fully factorial experiment designed to quantify the direction and strength of neighbor effects by focusing on changes in fungal community species composition and implications for seedling growth (a proxy for community function). We found that neighbor effects on the composition and function of adjacent communities follow a dominance hierarchy. Specifically, mycorrhizal communities established from soils collected in Douglas-fir plantations were both the least sensitive to neighbor effects, and exerted the strongest influence on their neighbors by driving convergence in neighbor community composition and increasing neighbor seedling vigor. These results demonstrate that asymmetric neighbor effects mediated by ecological history can determine both community composition and function.

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